Centrifugal fan



July 21, 19 36. HIBAENNINGER CENTRIFUGAL FAN '3 Sheets-Sheet 1 Filed Oct. 23, 1935 Wiiness July 21, 193

' H. BAENNINGERH 4 CENTRIFUGAL FAN 3 Sheets-Sheet 2 Filed Oct. 25, 1935 'July 21 193 H. BAENNINGER' CENTRIFUGAL FAN s Sheets-sheaf 3 Filed 001;. 25, 1955 Patented in 21, was

Application October 23, 1935, Serial No. 46,301 In Great Britain April 5, 1934 2 Claims. roman-114) The present invention relates to centrifugal fans and more particularly to fans-in which the output may be controlled by a whirl or spin im-.- parted to the entering fluid. t

B The principal object of the present invention is to provide a simple and eflicient means for controlling the spin imparted to the entering fluid.

With this and other objects in view, the pres-'- entinvention comprises the fan hereinafter de- 10 scribed and particularly defined in the claims.

In the acompanying drawings, Fig. 1 is a side elevation of a fan according to the present invention; Fig. 2 is an end elevation; Fig. 3 is a horizontal section showing the fan inlet box and 15 the guide vanes or 'flaps; Figs. 4 to 6 are views corresponding, respectively, with Figs. 1 to 3, showing a modification; Fig. 7 is a view illustrative of the difierential angular settings of the guide vanes or flaps shown in Figs. 4 to 6; and 2 Fig. 8 is a fragmentary elevation illustrative 01 a further modification.

Referring to the construction shown in Figs.

1 to 3, i, 2 and 3 denote the impeller or wheel,-

the impeller casing, and the inlet eye. respectively, 25 of a centrifugal fan.

Fluid enters the inlet eye 3 through an. inlet box of which the peripheral wall includes a cylindrical segment 4 co-axial with the impeller I and merging into tangents 5 forming-the top and 30 bottom walls of an inlet box. A plate 1 forms the vertiscal wall of the inlet box remote from the inlet eye For the purpose of imparting a controllable amount of pre-whirl to the fluid entering the inlet 35 eye 3, there are fitted within the inlet 6 of the inlet box guide vanes 8-42 movable angularly about pivots l3ll, respectively, parallel to the impeller axis, and spaced vertically apart.

On the pivots l3, l4 and lb of the guide vanes '40 8, 9 and ID are secured arms l8, l9 and 29,

respectively, operatively interconnected by links 2|, 22. The arm I8 is connected by a link 23 to one arm 26 of a three-armed lever secured on lever 20 to be locked to the guideway 29 alter '5 adjustment. p

When the guide vanes 8I2 are in full open position, as shown in ordinary dotted lines in Fig. l, and in full lines in Fig. 2, they lie in spaced parallel relation in parallelism with the line of flow of fluid through the inlet 6, so that no pre- 5 whirl is imparted to the fluid entering the inlet eye 3 of the fan. When the guide vanes are in shut position, as indicated in chain-dotted lines in Fig. 1, they overlap one another and form a substantially uninterrupted polygonal wall op- 10 posed to the segment 4, and having a surface approximating an imaginary cylinder, which, includes the wall 5. When, however, the guide vanes are angularly set between their limiting positions, they form deflecting louvres for the fluid stream entering the inlet G-and impart to said stream a predetermined amount of pre-whirl in the direction of rotation of the impeller i, indicated by the 'arrow A in Fig. 1, said amount increasing as the guide vanes are moved away from neutral or full open position. The components l8-28 of the vane-operating link system are so proportioned that the guide vanes perform diflerential angular adjusting movements. and in their angular settings the guide vanes are disposed substantially tangential to the whirling volume of fluid within the inlet box.

It will be seen thatthe guide vanes 8- are angularly movable in the same direction, while the guide vane i2 is angularly movable in the direction counter to the direction of movement of the guide vanes 8i|. The guide vane [2, when in neutral or full open position, lies flat against the adjacent wall 5 of the inlet box.

The pivots l3-l'| of the guide vanes lie in, or

, closely adjacent to the planes of the guide vanes.

In the modification shown in Figs. 4-7, guide vanes 29-33 are employed. The guide vanes 283l are provided with brackets 29 30' and 3|, respectively, to offset the vanes from their respective pivots, so that these guide vanes project into the whirl chamber within the inlet box to a considerably less extent than do the corresponding guide vanes 8-40 oi Figs. 1-3, particu larly when in full open position, it being under,- stood that excessive projection of the guide vanes into the whirl chamber will interfere with free 1 whirling motion of the fluid. The pivots 40, ll, 42 and 43 for the vanes 29-32 respectively are not arranged in a vertical plane as in Fig. 1, but are disposed on a curved surface. The vaneoperating link system shown is a simple modiflcation of that described with reference to Figs.

' 1-3, and will beunderstood without i'urther explanation. Fig. 7 shows the diiierential angular settings of the guide vanes 29-33.

Fig. 8 shows a modifled vane-operating arrangement contrived to permit the guide vanes to be moved reversely from neutral position .and so to impart pre-whirl to the fluid in the direction counter to thedirection oi! rotation 01' the impeller l According to this arangement, the vanes 3| and. 32 are operatively interconnected by toothed gear elements 34, 35 and 36, the gear element 34 being connected to the other guide vanes by a link system, and the gear element 36 being connected to'the guide vane 33 through the medium of a telescopic strut 31 including a compression spring 38. The vane 33, like the vanewhich corresponds to the full open position of the guide vanes, the strut 31 will telescope and allow the vanes 29-32 to beangularly set to 1 impart pre-whiri to the fluid in the direction counter to the direction 01 rotation of the impeller I.

The invention having been thus described. what is claimed is:

1. A centrifugal ian comprising a wheel. a casing having an eye. an inlet box to conduct fluid to the eye, a plurality of pivoted guide vanes in the inlet box at one side of the eye, one of the guide vanes being pivoted immediately adjacent to the casing to lie against the casing in open position, and means for simultaneously adjusting the vanes about their pivots. said means having provision tor moving the vane adjacent the casing in the opposite angular sense from the other vanes.

2. A centrifugal -fan comprising a wheel, a casing having an eye, an inlet box to conduct fluid to the eye, a'plurality of pivoted guide vanes in the iiflet box'at one side of theeye and arranged to be in substantial parallelism in wide open position, one of the vanes being pivoted immediately adjacent the casing, means for simultaneously adjusting the vanes angularly to impart a whirl to the fluid in one direction, said means having provision for moving the vane adjacent the casing in the opposite angular sense from the other vanes, and means permitting movement of said other vanes to impart a whirl in the cpposite direction without movement of the vane adjacent the casing. i

HERMANN BAENNINGER. 

